The frightening incident happened on Wednesday night at around 9.30pm in Ardee, Co Louth.
Country singer Mary had just come out of the Spar shop on Ardee's Main Street and sat into her car when a young guy wearing a hoodie and mask opened her door and took her handbag.
While badly shaked by what happened, fortunately Mary was not injured.
The bag contained a number of items that Mary says were of sentimental value, and she has appealed for the public's help to get her belongings back.
Speaking of the harrowing experience in a post on her Facebook page, Mary said it happened so quickly that she was unable to react.
The culprit ran off and jumped into a waiting car with two other youths in it, and which had been parked in the Old Credit Union car park.
“It happened so quickly that I was unable to react. Along with the usual credit cards/money/passport/driving licence etc., a number of very personal items were also stolen that are very important and sentimental to me," Mary posted on Facebook.
"The bag was a leopard skin type hold-all style. If you come across it or have any info that might help in retrieving it, I would be really grateful.
“I was very traumatised as a result… and thanks to some local people who witnessed what happened and came to my aid, and also the local Gardai who arrived on the scene very quickly."
Mary said it was the second incident like this that had taken place in the area in the last few days.
The singer from Lobinstown, Co. Meath, toured with Daniel O’Donnell for 32 years before leaving in recent years to pursue her solo work.
Mary had got her big break in 1987 when she won a Sunday World Search for a Star contest where Daniel O’Donnell’s then manager Sean Reilly was in the audience.
“Daniel was about to do his first U.K. tour and Sean asked if I would be interested in doing an audition to join the show as the opening act,” she told the Sunday World recently.
“I didn’t know then that I would go on to work with Daniel for the next 32 years!”
Speaking of her decision to leave Daniel and pursue some unfulfilled ambitions of her own, she said: “When you’re working with someone you are living their dream, you’re not living your own dream. You are in their shadow because it’s their show and you’re just there to fill in the gaps and the spaces, even though we were doing a lot together as well.
“If you are an artist working for an artist you don’t get much chance to fulfil what you want to do. I did enjoy every minute of being on his shows. We had a great time, we did two duet albums. People still request a lot of those songs, our voices blended well together. But I want to do some stuff on my own now.”
•Mary has asked anyone with information or dashcam footage to contact Ardee Garda Station on (041) 6871134.